Airplane engine controller



c. H. JQRGENSEN Erm. 2,516,123

AIRPLANE ENGINE CONTROLLER July 25, 1950 '7 .Sheets-Sheet 1 Filed April 10, 1944 .3 3 Ban@ SQ July 25, 1950 H. JoRGENsEN ErAL 2,516,123

AIRPLANE ENGINE CONTROLLER,

Filed April 1o, 1944 7 sheets-sheet 2 Zaad; /Jf

INVENTOR ATToRNEy/f July 25, 1950 c. H. JoRGENsx-:N ETAL 2,516,123

AIRPLANE ENGINE CONTRLLER 7 Sheets-Sheet 3 Filed April 10, 1944 INVENTOR m Mw m w w www M@ July 25, 1950 c. H. JoRGl-:NEN ETAL 2,516,123

AIRPLANE ENGINE cqNTRoLLER Mw g5 w50 C. H. @MENSEN ETAL 2,516,123

AIRPLANE ENGINE CONTROLLER 7 Sheets-Sheet 5 Filed April l0, 1944 L A N E s N E G R O J H C AIRPLANE ENGINE CONTROLLER 7 Sheets-Sheet 6 Filed April 10. 1944 w.. 0 c 6 r INVENTORS July 25, M950 c. H. JORGENSEN Erm.

AIRPLANE: NGINE CONTROLLER Filed April 10, 1944 7 Sheets-Sheet 7 Patented July 25, 1950 UNITED STATES PATENT YOFFICE AIRPLANE ENGINE CONTROLLER Clarence H. Jorgensen and William H. Taylor, Anderson, Ind., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware `Application April 10, 1944, Serial No. 530,280

This invention relates to apparatus for controlling the pressure of the air or fuel mixture in the intake passage of an internal combustion engine supercharged by an engine driven supercharger and by an auxiliary supercharger having variable speed driving means.

It is an object of the present invention to provide a controlling unit for determining the position of a throttle valve in the air or fuel mixture intake of the engine and for determining the speed of the auxiliary supercharger. The unit provides manual control means for selecting a pressure to be maintained in the engine intake and means responsive to divergencies from a selected pressure for effecting thru the operation of a servo-motor that movement of the throttle which is required to maintain the selected pressure. The controller unit provides a second servomotor for actuating an element for changing the speed of the auxiliary supercharger. This servomotor is under control by the member which selects the pressure to be maintained and is under control b'y an aneroid whereby the speed of auxiliary supercharger can be increased as the pressure selection increases and also as the altitude increases. In the higher range of pressure selections, movement of the speed changing element is effected jointly by the second servomotor and by the manually operated member which controls the pressure selection.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. l' is in part a side elevation` of thevcontroller unit and in part a diagrammatic representation of the supercharging system of the engine.

Figs. 2 and 3 taken together constitute a full scale side elevation of the controller.

Figs. 4 and 5 taken together constitute a longitudinal sectional view taken principally on the line 4-4 of Fig. 6.

Fig. 6 is an end view looking in the direction of arrow 6 of Figs. 2 and 4.

Fig. 'I is a view on the plane of the line 1--1 of Fig. 2L

Fig. 8 is a sectional view on 4 and 10.

' Fig. 9 is a sectional view on line 9-3 of Figs. 4 and 11.

Figs. 10 and 11 are respectively sectional views taken on the lines ll-v-Il and II-II of Fig. 8,

line of Figs.

2 Whereas the lower portion of Fig. 4 is a sectional view on line 4-4 of Fig. 8.

Fig. 12 is a. sectional view on Fig. 4.

Fig. 13 is a, sectional view on line |3|3 of Fig. 12.

Referring to Fig. 1, the air or fuel mixture duct of the engine comprises an air scoop 20 connected with carburetor 2|, pipe 22 connecting carburetor 2| with auxiliary supercharger 23 connected by pipe 24 with main supercharger 25 connected with engine intake 26. The air passing thru the carburetor is controlled by a throttle valve V. Metered fuel passes from the carburetor 2| thru a pipe 2l and terminating in a nozzle 28 adjacent the supercharged impeller 29 connected with an engine driven shaft 30.

'I'he auxiliary supercharger 23 may be driven at variable speed in any suitable manner as by an exhaust turbine or by an infinitely variable speed drive such as a hydraulic coupling 3| which comprises a driving vane 32 connected with an engine driven shaft 33 and a driven vane 34 connected with a tubular shaft 35 connected by gears 3G and 3l with a shaft 38 which drives the impeller 39 of the auxiliary supercharger. The hydraullc fluid or oil which provides the medium for transmitting motion from the vane 32 to the vane 34 is conducted thru the tubular shaft 35 and thru the narrow space 40 to the vane members. The oil receiving chamber within the vane members is connected by holes 4| with the interior of a housing 42 attached to the'vane member 32. The rotary liquid level within the housing 42 is the same as Within the vane members 32 and 34. The coupling ratio between the shafts 33 and 35 is determined by the distance between the axis of these shafts and the rotary liquid level which is determined by the position of a tube 43 opening at 44 into the body of coupling fluid and opening at into a drain member 46 from which oil is passed by means of a scavenger pump (not shown) to an oil tank from which oil is forced under pressure to the shaft 35. The tube 43 operates to scoop the oil from the housing 42 and therefore will be termed hereafter the "coupling scoop. It is apparent thaty the coupling slip is greatest and the speed of the supercharger 23 least when the opening 44 of the scoop is furthest from the axis of shaft 33 and that, as the lscoop is moved down in Fig. 1 to bring the end 44 nearer to the shaft 33, 'the coupling slippage decreases and the speed of the supercharger 23 increases.

The control unit which constitutes an embodiline I2-I2 of ment of the present invention is designated in its entirety by numeral 50. The controller 50 comprises a housing member 5| which encloses a servo-motorv for operating the valve V, a housing member 52 which encloses a servo-motor for operating the couplin-g scoop 43, a back plate or cover 53, a cam housing 54 and a cam housing cover- 55. These parts are secured together in any suitable manner.

Referring to Figs. 1 and 3, 60 designates the main control lever connected as shown diagrammatically in Fig. l by link 6| with the pilots control lever 62 which is pivoted at 63 and which can be frlctionally retained in engagement with a sector 64 by any suitable means not shown. Lever 60 is attached to shaft 65 which is pivotally supported by the housing 54 and which is connected with a cam 66 (Fig. 5) having a slot or race 61 receiving a roller 68 connected with a lever 69 connected with a shaft 10 which is also pivotally supported by the housing 54. Shaft 10 is connected with a lever 1| for making connection with a mechanism (not shown) which controls the governed speed of the engine. Therefore, the speed of the engine can be controlled by the pilots control lever 62. Counterclockwise rotation of cam 66 into the passage 66a is limited by engagement of the cam with a stop screw 12 locked in adjusted position by a nut 13.

The shaft 65 is connected with a short lever 15 (Figs. 3 and 5) and a longer lever 16. Lever 15 carries stud 11 providing a fulcrum for a bell crank lever having arms 18 and 19. Arm 18 is connected by link 80 (Fig. 1) with a lever 8| attached to a shaft 82 which carries the throttle valve V. Lever 19 is connected by link 85 with servo-motor piston rod 86 which extends thru a packing member 81 and a bushing 88 and a cylinder head member 89 and is connected with a piston 80 movable within a cylinder 9| as illustrated in Fig. 4. Rod 86 is guided by cylinder head member 92. In the left end of cylinder 9| a spring 93, located between the head 92 and the piston 90, urges the piston toward the right in Fig. 4. This servo-motor is operated`by pressure fluid entering through a pipe 95 (Fig. 2) connected. with hole 96 in plate 53, with hole 91 in housing 52, with hole 98 in housing 5| which is connected with passage 98a (Fig. 12). Passage 98a is connected with a groove 99 in a valve guide |00 -having a plurality of ports leading to the interior or central bore of the guide. A valve |02 having llands |03 and |04 (Figs. 4 and 5) controls the distribution of the pressure of oil to ports |05 and |06 which are connected with grooves 01 and |08 respectively provided by the guide |00, which is provided with a flange |09 (Fig. 5) which is urged by a spring washer ||0 against a shoulder provided by the housing 5|. As shown in Fig. 13 the ports |05 are connected by the groove |01 with passages ||2 and I3 and a passage ||4 with the left end of the cylinder 9|. The end of the passage I4 appears in Fig. 4. The groove |08 is connected by al passage ||5 (Fig. 5) with the right end of the cylinder 9|. When valve |02 moves right to connect the ports |0| with the ports |06 the piston 90 will move left and oil in the left end of the piston will be discharged through passages 4, ||3, ||2, ports |05 and out through the central bore of the guide |00 into a chamber ||6 (Fig. 4) provided by the housing 5|. When the valve |02 moves left to connect the ports 0| and |05 the piston 90 will move right and oil in the right end of the cylinder will be discharged through passage ||5 and ports |06 into the central bore of guide |00 and out through the passages ||1 and ||8 (Fig. 13) and into the chamber ||6 from which it returns to the engine oil system.

, The valve |02 is positioned jointly by manually operated means for selectinga pressure to be maintained and by a device responsive to engine intake pressure. For this purpose the lever 16, which is moved by the pilots control lever through the main control lever 60 of the regulator, is connected .by a link |20 with a lever |2| connected with a shaft |22 which, as shown in Fig. 4, carries a pressure selecting cam |23 which cooperates with a lever |24 pivoted at |25 and urged by a spring |26 against the cam |23. The lower end of lever |24 is connected by a pin |21 and a link |28 with the valve |02. The pivot |25 is supported by a bridge |30 connecting the movable end plates |3| and |32 ofAbellows |33 and |34, respectively, having relatively fixed end plates |35 and |36. Between the plates |3| and |35 of bellows |33, springs |31 and |38 are confined under compression; and between plates |32 and |36 of bellows |34, a spring |39 is confined. These springs are so calibrated that the pivot |25 will move in a denite and substantial linear relation with respect to changes in the pressure within the bellows |34. The bellows |33 and |34 have substantially the same external area so that bellows |33. which is evacuated, compensates for variations in atmospheric pressure aiecting the bellows |34. Therefore, the bellows system responds only to variations in pressure within the bellows |34 which is connected with the engine intake manifold through a hole in a plate |40 (attached to the plate |36), passage |4|, passage |42 (Fig. 2) and passage |43 in housing 5|, passage |44 in housing 52 and passage |45 in cover 53 and a pipe |46 (Fig. 1) connecting the hole in cover 53 with the intake manifold 26.

The bellows system is initially adjusted by turning a screw |50 (Fig. 2) carrying an eccentric pin |5| (Fig. 4) received by groove |52 provided by the cylindrical extension |53 of the bellows plate |35 which is slidable in a boss |54 provided by wall |55 of the housing 52. The screw |50 is secured in adjusted position by lock nut |56 (Fig. 2). The lock nut is protected by a cover |51 attached to screw |50 by a screw |58.

Fig. 4 shows the pressure selecting cam |23 in its position for selecting the lowest pressure for .engine idling. When the pilot wishes to take off he moves the lever 62 counterclockwise thereby effecting counterclockwise movement of levers 60, shaft 65, lever 16, lever |2|, shaft |22 and cam |23. As the pivot 11 carried by lever 15 moves toward the right in Fig. 1 the bell crank lever arm 19, being pivotally connected at 19a with link 85, will be caused to rotate around its pivotal connection 19a; and the bell crank as a whole will rotate clockwise about the pivot 11 thereby causing the link to move toward the right and the valve V to open to some position which will cause the intake pressure to rise to a value somewhat less than the pressure selected by movement of cam |23. As the cam |23 is caused to move counterclockwise in the manner described, the lever |24 will rotate counterclockwise and the valve |02 will move to the right to connect the pressure fluid with the right end of the cylinder thereby causing the piston to move left to increase the opening of the throttle in order that the pressure will be raised to the selected value. As the pressure increases the bellows |34 expands to cause the pivot |25 to move left to eii'ect a closing movement of the valve |02 in order to bring it into 'a position of equilibrium, as shown inFigs. 4 and 5. As the altitude increases the servo-motor continues to open the valve V in order to maintain the selected pressure. At a certain altitude the valve Y V will have been moved as wide open as possible through the joint operation of the manual and automatic controls. After that altitude is exceeded, the intake pressure will begin to decrease;

hence, that altitude is called the critical altia pressure selecting device'and of means respon-` sive to engine intake pressure for effecting through a servo-motor the positioning of the throttle valve in such manner as to correct for any divergency of intake pressure from the selected or standard pressure.

The supercharger 25, which is directly driven by the engine and is therefore known as the engine stage supercharger, operates to provide the required supercharging for idling and part-load operation of the engine. At the same time the auxiliary supercharger 23 is being driven by the engine through the shaft 33 and hydraulic coupling 3| at a speed such that no drag is placed on the engine supercharger 25. Therefore, the normal position of the coupling scoop 43 is such that the minimum vslip of the coupling provides a speed of the supercharger 23 suflicient to overcome the friction of the movement of air to the supercharger 25. In fact there may be a slight boost of the supercharger 25 -by the supercharger 23 under part-load conditions.

When the engine is required to operate for take-ofi or emergency, or even under cruising conditions, it is necessary to operate the auxiliary supercharger 23 at an increased speed in order that it will provide the boost necessary to maintain the required pressure up t high altitude. For this purpose coupling scoop 43 is placed under the joint control directly by the main control lever 60 and by a servo-motor the operation of which is under joint control by the main control lever 60 and by an aneroid. As shown in Fig. 1, coupling scoop 43 is connected by link |60 with a bell crank lever |6| pivoted at |62 and connected by link |63 with lever |64, pivoted at |65 and provided with a cam slot having parts |66a and |6617, both for receiving a pin |61 on arm |68, pivoted at |69 on housing 52 and integral with an arm |10 connected by a link |1| with lever 60. The portion |66a of the cam slot is arcuate, having its center of curvature at the center of pivot |69. Therefore, during certain movements of lever 60 as from 60a to 60h (Fig. 1)

|86 fixed to a shaft |81 (Fig. 5), fastened to a bell crank lever |88 (Fig. 1) which carries the pivot |65 for lever |64 and which is connected by a link |89 with a lever |90 attached'to a shaft |9| (Fig) 2) which eccentrioallysupports the shaft |22 ofthe pressure selecting cam |23 (Fig. 4). The position of the piston |8| is controlled by a "alve |95 having lands |96 and |91`respectivel; for controlling ports |88 (Fig. 11) and |99 (Fig. lll)V provided by the tube |82. The servo-motor operated by oil under pressure which enters a passage 200 connected with an oil pressure pipe 200a (Fig. 4). Passage 200 is in communication with a groove 20| of piston |8| in any position thereof. The groove 20| is connected by radial passages 202 of the piston with diametrically opposite slots 203 of the tube |82 (Fig. 4) and these slots are connected by holes 204 with the annular groove 205 between the lands of the valve |95. In any'equilibrium position of the piston the ports |98 and |99'are closed by the valve lands |96 and |91 respectively. It the valve |95 moves to the right of its position shown'in Fig. 10 then the groove 205 receiving oil under pressure is connected by the ports |99 with two diametrically opposite grooves 206 of the tube |82 which are connected by passages for selecting pressures in the lower range', there is no movement of lever |64 directly by the lever 60. However,L during movement of lever in the higher pressure range the pin |61 cooperates with the oblique portion cam slot portion |66bto elect clockwise movement of the lever |64 as lever 60 moves from 60b to 60c when selecting higher pressures.

The servo-motor for controlling the hydraulic coupling comprises a cylinder |80 integral with the housing 52 cooperating with a piston |8| which is attached to a tube |82 connected by a pin |83, a link |84 and a pin |85 with a lever 201 with the left end of the cylinder |80. Therefore the piston |8| will move right to a position such that the ports |99 are closed by the lands |91, and movement of the piston right will cease. If valve is moved left from the position shown in Fig. 11, groove 205 will be connected by ports |98 with diametrically opposite grooves 208 of the tube |82 which are connected by holes 209 with the right end of the cylinder |80.

Therefore, the piston |8| will be urged toward the left and will so move when there is clearance between the piston and the left end wall of the cylinder. This movement will continue until the ports |98 become closed by the land |96. Therefore, under oil pressure, the piston will follow the valve. The position of the valve determines the position of the piston and of the coupling scoop 43 (Fig. l). In case of failure of the oil pressure, the coupling scoop is returned to position of greatest slip or lowest gear ratio by a spring 2|0 located between the -piston |8| and a cylinder head member 2|| providing a bearing 2|2 for the tube |82; The head 2|| is retained by a tubular plug 2| 3. The left end of the `rod |82 is guided by a bushing 2|4 provided vby the housing 52. To permit assembling the 'pin and valve within the cylinder the housing 52 is provided with a threaded opening 2 l5 closed by a plug 2|6 (Fig. 5). A drain conduit d is illustrated, 4through which oil from the housing 52 is returned to the source of supply.

The location of the valve`y |95 is determined jointly by altitude responsive means and by means controlled by the main control lever and operated in coordination with movements of the selector cam 23. For this purpose the selector cam operating lever |2| is connected by a link 220 with an arm 22| attached to a shaft 222 carrying acam 223 against which'a spring 224 urges lever 225 having av oating fulcrum pin 226 and connected at its lower end by a pin 221 and by a wire link 228 with the valve |95. The floating fulcrum pin 226 is supported by a member 230 integral. with the right plate 23| of an aneroid bellows 232 having a left plate 233 which can be secured in a desired position of adjustment. The right end of the member 230 carriesan extension 284 slidable in a bearing 235 provided by the wall 1 |33 of housing 52. A boss 235 extending from the plate 233 is siidably supported at 231 by the cover plate 53. Rotation oi' the plate 233 is pre'- vented by a dowel pin 23`| nxed to the plate 233 and slidable thru a recess 233 in the cover 233. For the purpose of adjusting the plate 233 and the position of the lever 225, .a boss 243'provided by the cover plate 53 threadedly receives a screw 24| thru which extends a screw 242 which is threadedly attached to the member to 233. The

screw 242 Ais removed thereby -permitting removal' cfa guard 243. Then the screw 24| is turned to the desired position and it is secured by a selflocking nut 244-. Then the cap 243 and the screw 242 are replaced. the screw being turned so as to draw the part 235 against the right end of the screw 24|.

The function of the cam 223 is to determine the initial position of the coupling scroop 43.

vAs a higher pressure is selected as a result oi counterclockwise rotation of camv |23 there will be a corresponding rotation of cam 223 and a counterclockwise rotation of the lever 225 and the movement of the valve |95 toward the right. This causes the coupling scoop to be moved from its position of greater slip, to a position of lesser slip thereby providing a coupling ratio which is suitable for that selected pressure at ground level. As altitude increases the aneroid 232'will expand and cause floating pin 226 to move toward the right thereby causing movements of the valve |95 to the right in accordance with altitude increase. The cam 223 and the In order to maintain in theI space within the main housing member |52 the same pressure as is maintained in the air scoop or carburetor intake, a boss 253 is formed on the outer surface of the plate or cover member 53 and is provided with a threaded opening 25| extending therethrough and communicating with the space inside the housing. A pipe 252 is adapted to be screwed into this threaded passage and extends as shown in Fig. 1 to the air scoop 20 which admits air to the carburetor. This pipe connects with the air scoop at a point anterior to the carburetor and communicates what ever pressure is maintained in the scoop at this point to the space within the housing member 52. leading from this housing 52, at the lower portion thereof, is an oil pipe d. 4

While the embodiment of the present invention as herein disclosed, constitutes a preferred form. it is to be understood that other forms might be adopted. all coming within the scope oi' the claims which follow.

What is claimed is as follows:

1. Apparatus for controlling the intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, variable speed vmeans for driving the auxiliary supercharger, a member -for controlling the variable speed driving means, athrottle valve for controlling intake pressure, a manually operated member. means operated thereby for moving the throttle valve and for selecting' a pressure to` be maintained, a servo-motor for moving the throtaneroid bellows 232 are so constructed and calibrated as to effect thru the hydraulic coupling an increase of the speed of the supercharger 23 in a manner such that the supercharger will operate at maximum speed at the required high altitude. Obviously the calibration mustvbe such that the pressure obtained at that high altitude must be belowthe borderline detonating pressure.- In other words, the maximum movement of the piston toward the right must be no more than that required to cause the pressure to be within safe limits.

For certain high pressure selections, such as for take oif and emergency, it is necessary to start with the coupling scoop end 44 much nearer to the shaft 33 than it would be when controlled solely by the cam 233 and the aneroid 232. Therefore the coupling scoop is placed under the `ioint control of the lever and the lower servo-motor. For positions of the lever 50 between a and 60h (Fig. 1). no movement of the lever |54takes place, since the pin |51 moves through the radial portion |55a of the slot. Between positions of h and 60e of the lever 53 the pin |31 engages the inclined or oblique portion |45b of lever |64 thereby causing it to move clockwise to cause movement of the coupling scoopend 44 toward the shaft 33. Therefore the ground level coupling ratio of the hydraulic coupling is increased from the minimum when v the pressure selection is for take-ofi or higher.

In response to operation of the lower servomotor, when increasing the coupling ratio. the

selected pressure is raised to cause the engine to develop the additional power required to drive the supercharger 23 at higher speed. This is4 accomplished by effecting clockwise rotation of shaft |3| which eccentrically supports selector cam shaft |22 through the mechanism whichl includes the lever |85 (Fig. 1) rotated clockwise by movement of piston |8| toward the right (Fig. 4) link |33 and lever |33.

tle valve, means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure, a second servo-motor for moving the speed-controlling member. an aneroid, means under control by the manually operated member and by the aneroid for controlling the second servo-motor and means operated by the second servo-motor for modifying the status of the pressure selecting means to increase the selected pressure as the speed of the auxiliary supercharger is increased.

2. Apparatus for controlling the intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, variable speed means for driving the auxiliary supercharger, a member for controlling the variable speed driving means. a throttle valve for controlling intake pressure, a manually operated member, means operated thereby for moving the throttle valve and for selecting a pressure to be maintained, a servo-motor for moving the throttle valve. means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure, a second servo-motor for moving the speed-controlling member, an aneroid, means under control by the manually operated member and by the aneroid for controlling the second servo-motor and means under joint control by the second servo-motor and by the manually operated member for actuating the speed-controlling member.

3. Apparatus for controlling the intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, variable speed means for driving the auxiliary supercharger.' a member for controlling the variable speed driving means, a throttle valve for controlling intake pressure. a manually operated member, means operatedthereby for moving the throttle valve and forV selecting a pressure to be maintained, a servo-motor for moving the throttle valve, means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure, a second servo-motor for moving the speed-controlling member, an aneroid, means under control by the manually operated member and by the aneroid for controlling the second` servo-motor, means operated by the second servo-motor for modifying the status of the pressure selecting means to increase the selected pressure as the speed of the auxiliary supercharger is increased and means under joint control by the second servo-motor and by the manually operated member for actuating the speedcontrolling member.

4. Apparatus for controlling the intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, variable speed lmeans for driving the auxiliary supercharger, a member for controlling the variable speed driving means, a throttle valve for controlling intake pressure, a manually operated member, means operated thereby for moving the throttle valve and for selecting a pressure to be maintained, a servo-motor for moving the throttle valve, means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure, a second servo-motor for moving theyspeedcontrolling member, said servo-motor comprising a cylinder and a piston mounted on a tubular vpiston rod, ports provided by the rod for controlling the flow of pressure fluid to either side of the piston, a control valve slidable within the rod for controlling said ports, an aneroid, and means under control by the lmanually operated member and'by the aneroid for determining the position of the control V`valve.

5. Apparatus kfor controlling the 'intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, variable speed means for driving the auxiliary supercharger, a member for controlling the variable yspeed driving means, a throttlevalve .for controlling intake-pressure, a manually operated member, means operated thereby for moving the throttle valve and for selecting a pressure to be maintained, a servo-motor for moving the throttle valve, means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for'maintaning the selected pres.

sure, a second servo-motor 'for moving the speedcontrolling member, said servo-motor comprising a cylinder and a piston mounted on a tubular piston rod, ports provided by the rod for controlling the iiow of pressure fluid to either side of the piston, a control valve slidable within the rod for controlling said ports, a oating lever connected with the valve, an aneroid for positioningv the lever, and a cam operated by the manually operated means in coordination `Vwith the operation of the pressure selecting means for positioning the lever` 6. Apparatus for controlling the intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, variable speed means for driving the auxiliary supercharger, a member for controlling the variable speed driving means, a throttle valve for controlling intake pressure, a manually operated member, means operated thereby for moving the throttle valve and for selecting a pressure to be maintained, a servo-motor for moving the throttle valve, means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure, a second servo-motor for moving the speedcqntrolling'-member, an aneroid, means under control by the manually operated member and by the aneroid for controlling the second servomotor and a mechanism for moving the variable speed controlling member and including a oating lever, means for transmitting motion from the second servo-motor to the lever, and means responding to movement of the manually operated member when selecting certain pressures for imparting movement to the lever.

7. Apparatus for controlling the intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, variable speed means for driving the auxiliary supercharger, a member for controlling the variable speed driving means, a throttle valve for controlling intake pressure, a manually operated member, means operated thereby for moving the throttle valve and for selecting a pressure to be maintained, a servo-motor for moving the throttle valve, means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure, a second servo-motor for moving the speed-controlling member, means for determining the initial position of the speed-controlling member in response to movement of the manually operated member to select certain pressures, means controlled by altitude and by the manually operated member for determining the extent of movement of the speed controlling member by the second servo-motor, means operated by the second servo-motor for modifying the status of the pressure selecting means to increase the selected pressure as the speed of the auxiliary supercharge is increased.

8. Apparatus for controlling the intake pressure-of 'anairplane engine having a main supercharger and an auxiliary supercharger, means for driving the auxiliary supercharger, a variable 'speed coupling device between the driving means and the supercharger, ,a member for adjusting the coupling to cause thesupercharger to be driven at progressively varying speeds, a throttle valve for controlling intake pressure, a manually operated member, means operated thereby for moving the 'throttle valveand for selecting a pressure to be maintained, a servo-motor Vfor moving the throttle valve, means Aresponsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure, a second servo-motor for operating said member to vary the speed at which the supercharger is operated by its driving means, an aneroid, and means under control of the aneroid and said manuallyl operated member for controlling the operation of said second servo-motor.

9. Apparatus for controlling the intake pressure of an airplane engine having a main supercharger and an auxiliary supercharger, means for driving the auxiliary supercharger, a variable speed coupling device between the driving means and the supercharger. a member for adjusting ll 1 the coupling to cause the supercharger to be driven at progressively varying speeds, a throttle valve for controlling intake pressure, a manually operated member, means operated thereby for moving the throttle valve and for selecting a pressure to be maintained, a servo-motor for moving the throttle valve, means responsive to the pressure selecting means and to engine intake pressure for controlling the servo-motor in order to position the throttle valve for maintaining the selected pressure. a second servo-motor for operating the member for controlling the action of said coupling, means for determining the initial position of said member in response to movement oi' the manually operable member to select some desired pressure,yand means ccntrolled by altitude and by the manually operable member for determining the extent of movement of the member which controls the action of said variable speed coupling.

10. Apparatus for controlling the intake pressure of an aircraft engine having main and auxiliary superchargers, means for driving the auxiliary supercharger. a variable speed coupling device between the driving means and the auxiliary supercharger, a member for adjusting the coupling to cause the supercharger to be driven at progressively varying speeds, a throttle valve for controlling intake pressure, a manually operated member, means operated thereby for moving the throttle valve and for selecting a pressure to be maintained, a hydraulic servo-motor i'or moving said valve, a pressure selecting cam `operated member, and means under joint control by the second cam and by the aneroid for controlling the action oi the second servo-motor.

` v CLARENCE H. JORGENSEN.

WILLIAM H. TAYLOR.

REFERENCES CITED The following references are oi record in the ille oi this patent:

UNITED STATES lPirI'EN'rs Number Name Date 2,018,914 Endres Oct. 29, 1935 2,217,364 Halford Oct. 8, 1940 2,290,884 y Kollmann July 28, 1942 2,297,235 Muller Sept. 29, 1942 2,336,844 Buck Dec. 14, 1943 2,355,759 Stokes Aug. 15, 1944 FOREIGN PATENTS.

Number Country Date 454,154 Britain Sept. 21, 1936 

